Generally speaking, the lock control systems of the prior art are equipped with a lock acutuator disposed on the door adjacent to the driver's seat whereby the driver can effect the locking and unlocking operation of all the doors of a vehicle at the same time.
As shown in FIG. 1, the actuator 1 is provided at the top end thereof with an engagement ring 11 connected upward to a lock knob by means of an attachment rod and other necessary links. The engagement ring is downward coupled to a rack member 13 disposed within a casing 12. The rack member 13 disposed within a casing 12. The rack member 13 is further extended into an actuation rod 14 at the bottom end thereof. On the engagement ring being depressed to its lowest position, the actuation rod 14 is moved to abut a limiting switch 15. The rack member 13 is in engagement with a gear 16 of a set of coaxially disposed gears. A gear 18 attached to the shaft of a motor 17 is engaged with the largest gear of the gear set so that the actuator 1 can make the engagement ring 11 to move upward or downward by the operation of the motor, resulting in the automatic lift and depression of the lock knob.
In the prior art lock control systems, the limiting switch 15 is only mounted in one of the actuators generally disposed on the front door next to the driver's seat. Therefore, as shown in FIG. 2, the wiring diagram, the actuator 1A has two wires W1, W2 associated with the motor; and two signal wires S1, S2 and a ground line G are coupled to the limiting switch 15. In the meanwhile, the other actuators 1B, 1C, 1D mounted respectively on the other doors. As clearly shown in the same figure, all the actuators are coupled to an electronic module 2, the signal output from the limiting switch 15 is transmitted by way of S1, S2 to the electronic module 2 which effect the control of other actuators 1B, 1C, 1D to perform the same operation.
It is now clearly seen that the prior art lock control system has a relatively complicated wiring connections. Thus, the installation of the system is not easily performed. This constitutes one of the disadvantages of the prior art. Furthermore, only one of the actuator is equipped with the limiting switch such that the doors can be automatically operated by this actuator. If all doors are desired to effect automatic control over the others, each actuator must be installed with an extra limiting switch accordingly, causing the raise of the cost with the wiring becoming more complicated.
Besides, in the prior art lock system only the driver's door is equipped with the limiting-switch operated actuator so that the driver is not able to detect the rear doors being opened by the passengers, especially small children Thus, accidents can be easily caused as a result thereof.
Therefore, the primary object of the present invention is to provide an improved central lock control system which eliminates the disadvantages of the prior art power lock system.
One other object of the present invention is to provide an improved central lock control system which can transform the clockwise or counterclockwise rotation of the motor, produced by the pull or depression of the lock knobs of the front doors, into an inductive voltage signal which is delivered to an electronic module to be amplified, shaped and compared, and actuates a relay to cause the other motors of the actuators to spin clockwise or counterclockwise accordingly.
One still other object of the present invention is to provide an improved central lock control system which is free of the use of a limiting switch so that the installation thereof is made simplified. Besides, the actuation of any lock knobs of the doors can be transformed into signals delivered to an electronic module for effecting the control of other doors.
One still other object of the present invention is to provide an improved central lock control system which is characterized in that the door-locking signal from either of the rear doors is transferred to a semi-automatic circuit, and the signal produced by the motor in locking the rear door is crossed out; only the signal produced by the motor in unlocking the rear door is delivered to the electronical control unit so to simultaneously unlock the other doors. Thus, the driver can notice immediately the rear doors being unlocked by kids sitting in the back seat, and take thereby proper actions small children can be protected in a safer manner from possible accidents.